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AKwUvBwUCqGHdrF3Sata2xGJfJYlhTESfa32rUHrZ/v4YIMl9MrFJTfMwvnOCfS80LVcd1xh0td3nlm5Vg==@kvack.org X-Gm-Message-State: AFuF++n9hMkj8VUoJWNF83Zl/8vSjaUqevAtyUmMXh27y7tNjj4x1l6y u+1mjbKGuMgVFFFHCT6n2/AuIr9Ej2F6CivW6aDJtTGTbgZNhnFeAw330F5KnoUuldz1UCarcDz MzIPuFw== X-Received: from dlbbq8.prod.google.com ([2002:a05:7022:6708:b0:143:6807:5e3b]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4c85:b0:38f:cfe2:fd3a with SMTP id 98e67ed59e1d1-39d77b1c383mr8988591a91.15.1789084071601; Thu, 10 Sep 2026 16:47:51 -0700 (PDT) Date: Thu, 10 Sep 2026 16:47:34 -0700 In-Reply-To: <20260910234737.1340642-1-surenb@google.com> Mime-Version: 1.0 References: <20260910234737.1340642-1-surenb@google.com> X-Mailer: git-send-email 2.55.0.1007.g17ff1f9808-goog Message-ID: <20260910234737.1340642-5-surenb@google.com> Subject: [PATCH v3 4/7] proc/task_mmu: remove special-casing of smap_gather_stats() start parameter From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: liam@infradead.org, ljs@kernel.org, vbabka@kernel.org, david@redhat.com, willy@infradead.org, jannh@google.com, paulmck@kernel.org, pfalcato@suse.de, xueyuan.chen21@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, surenb@google.com Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 0EB081C0008 X-Stat-Signature: 3p7ihi5f9uttoz3msnfomnuyrcg8mi6z X-HE-Tag: 1789084072-908130 X-HE-Meta: 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 en9XAfNW 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: smap_gather_stats() interprets its start parameter to mean vma->vm_start when it's set to 0. Eliminate this special interpretation and pass vma->vm_start explicitly when needed. Since smap_gather_stats() operates within a single VMA, we can replace walk_page_vma()/walk_page_range() calls with walk_page_range_vma() which is simpler and also can be called while holding per-VMA lock. No functional change intended. Suggested by: Lorenzo Stoakes Signed-off-by: Suren Baghdasaryan Reviewed-by: Liam R. Howlett (Oracle) --- fs/proc/task_mmu.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 3c40c9cbb9c9..ecce7ce116cb 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1246,21 +1246,27 @@ get_smaps_shmem_walk_ops(struct proc_maps_private *priv) return &smaps_shmem_walk_vma_lock_ops; } -/* - * Gather mem stats from @vma with the indicated beginning - * address @start, and keep them in @mss. +/** + * smap_gather_stats() - Gather mem stats from @vma. + * @priv: proc maps private state. + * @vma: The VMA to gather stats for. + * @mss: The accumulated stats. + * @start: The address from which to start. * - * Use vm_start of @vma as the beginning address if @start is 0. + * This gathers stats for the whole of the VMA unless the lock was dropped + * and VMA grew or got merged and we found it again, in which case we only + * gather stats for the remainder of the VMA range. */ static void smap_gather_stats(struct proc_maps_private *priv, struct vm_area_struct *vma, - struct mem_size_stats *mss, unsigned long start) + struct mem_size_stats *mss, + unsigned long start) { const struct mm_walk_ops *ops = get_smaps_walk_ops(priv); const bool is_partial = start > vma->vm_start; /* Invalid start */ - if (start >= vma->vm_end) + if (start < vma->vm_start || start >= vma->vm_end) return; if (vma == get_gate_vma(priv->lock_ctx.mm)) @@ -1285,10 +1291,7 @@ static void smap_gather_stats(struct proc_maps_private *priv, mss->swap += shmem_swapped; } - if (!start) - walk_page_vma(vma, ops, mss); - else - walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss); + walk_page_range_vma(vma, start, vma->vm_end, ops, mss); reacquire_rcu(priv); } @@ -1343,7 +1346,7 @@ static int show_smap(struct seq_file *m, void *v) struct vm_area_struct *vma = v; struct mem_size_stats mss = {}; - smap_gather_stats(priv, vma, &mss, 0); + smap_gather_stats(priv, vma, &mss, vma->vm_start); show_map_vma(m, vma); @@ -1396,7 +1399,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v) vma_start = vma->vm_start; do { - smap_gather_stats(priv, vma, &mss, 0); + smap_gather_stats(priv, vma, &mss, vma->vm_start); last_vma_end = vma->vm_end; /* @@ -1455,7 +1458,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v) /* Case 1 and 2 above */ if (vma->vm_start >= last_vma_end) { - smap_gather_stats(priv, vma, &mss, 0); + smap_gather_stats(priv, vma, &mss, vma->vm_start); last_vma_end = vma->vm_end; continue; } -- 2.55.0.1007.g17ff1f9808-goog